class: center, middle, inverse, title-slide # Drivers and typologies of biodiversity trends in global stream fish communities ## Joint Aquatic Science Meeting 2022 ### Alain Danet
1
, Xingli Giam
2
, Julian Olden
3
, Lise Comte
1
### 1:Illinois State University, 2:University of Tennessee, 3:Washington State University ### 2022-05-03 --- # Introduction ## Biodiversity in crisis .pull-left[ ### Key numbers 1. 25 % of evaluated species plant and animals are threatened 1. Average abundance of native species decrease by 20% in most of biomes 1. Most degraded ecosystems contains 76% less species, 39% less individuals than reference ones 1. Homogenization of community composition ] -- .pull-right[ ### Key causes 1. Land-use changes 1. Over-exploitation of resources 1. Climate change 1. Invasive exotic species Source: [IPBES](https://ipbes.net/sites/default/files/2020-02/ipbes_global_assessment_report_summary_for_policymakers_fr.pdf) ] .footnote[[Dornelas, Gotelli, McGill, et al. (2014)](https://science.sciencemag.org/content/344/6181/296); [Newbold, Hudson, Hill, et al. (2015)](https://www.nature.com/articles/nature14324)] ??? - Spatial comparison - Terrestrial Vertebrates, invertebrate and plants --- # Research questions How anthropogenic pressure drive the spatio-temporal trends of freshwater fish biodiversity? --- # Methods --- # Fish data - RivFishTime ([Comte, Carvajal-Quintero, Tedesco, et al., 2021](https://onlinelibrary.wiley.com/doi/abs/10.1111/geb.13210)): ??? - Selection for homogeneity of sampling - Spaning from 10 years to XX years --- # Biodiversity facets --- # Environmental variables ## Stream gradient - PCA ## Human pressure - Distribution of human footprint riveratlas / rivfishtime - Show match sampling and human footprint year ??? - Stream gradient: upstream to downstream - Human pressure: Rivfishtime have sites less degraded than global scale - Recent changes in human pressure: log2 --- # Statistical analysis - Hierarchical linear models: - `\(Y_i = \alpha + \Beta_1*\Log(time) + \sum_{j=1}\Beta_j X_j + \espilon_i\)` - `\(\alpha = \alpha_0 + a_k + a_l\)`; `\(a_k, a_l \sim \mathcal{N}(0,\,\sigma^{2})\)` - `\(\Beta_1 = \mu + b_k + b_l\)`; `\(b_k, b_l \sim \mathcal{N}(0,\,\sigma^{2})\)` - `\(k\)`: basin, `\(l\)`: site within basin -- - Main effects: - Time: Log(Year number) - Stream gradient (Upstream -> Downstream): PCA axis - Legacy of long term pressure: Human footprint 1993 - Recent change in pressure: Log 2 ratio of Human footprint (1993-2009) - Interactions: - Time X all other main effect - Time X main effect x main effect -- - Evaluated in bayesian INLA (Integrated Nested Laplaician Approximation) --- # Preliminary results 1. Positive temporal trends of species richness, total abundance & very weak evidence for percentage of exotic species ([Klink, Bowler, Gongalsky, et al., 2020](https://science.sciencemag.org/content/368/6489/417)). 1. We found high species recomposition over time ([Dornelas, Gotelli, McGill, et al., 2014](https://science.sciencemag.org/content/344/6181/296); [Blowes, Supp, Antão, et al., 2019a](https://www.sciencemag.org/lookup/doi/10.1126/science.aaw1620)) 1. Jaccard & Simpson based dissimilarity index have the same trends everywhere, indicating that composition changes are driven by abundant species 1. Community temporal changes in composition are mainly driven by turnover, i.e. change in species identity ([Blowes, Supp, Antão, et al., 2019a](https://www.sciencemag.org/lookup/doi/10.1126/science.aaw1620)) --- # Temporal dissimilarity <img src="jasm2022_files/figure-html/unnamed-chunk-3-1.png" width="100%" /> --- # Temporal dissimilarity Legacy of past and recent human pressure have a synergistic effect on temporal turnover <img src="jasm2022_files/figure-html/unnamed-chunk-4-1.png" width="100%" /> --- # Drivers of total abundance and species richness <img src="jasm2022_files/figure-html/unnamed-chunk-6-1.png" width="100%" /> --- # Drivers of total abundance and species richness <img src="jasm2022_files/figure-html/unnamed-chunk-7-1.png" width="100%" /> ??? - Global positive temporal trends of species richness and total abundance ([Klink, Bowler, Gongalsky, et al., 2020](https://science.sciencemag.org/content/368/6489/417)) - Higher abundances, richness and exotic species downstream - Higher richness but lower abundances in more degraded sites, but also higher percentage of exotic richness and abundances - Lower richness and abundance but also higher percentage of exotic richness and abundances in sites where human pressure increased recently --- # Drivers of total abundance and species richness <img src="jasm2022_files/figure-html/unnamed-chunk-9-1.png" width="100%" /> --- # Drivers of total abundance and species richness <img src="jasm2022_files/figure-html/unnamed-chunk-10-1.png" width="100%" /> ??? - Higher temporal trends of abundance, richness in more past degraded sites. Is it a sign of recovery? But no evidence of recovery in exotic species composition. So, recovery but not restauration ? (because exotic are often tolerant to degradation) - Evidence that recent increase in anthropogenic pressure decrease temporal trends of richness, abundance and increase in percentage of exotic species - Synergistic effect of long term degradation and stream gradient on exotic species (richness and abundances). Antagonistic effect on abundances and richness (very weak) - Recent increase of anthropogenic pressure increase temporal trends of percent of exotic species in long term degraded sites. Antagonistic effect on abundances temporal trends (decrease of recovery) --- # Drivers of biodiversity - Global positive temporal trends of species richness and total abundance ([Klink, Bowler, Gongalsky, et al., 2020](https://science.sciencemag.org/content/368/6489/417)), and more in long term degraded sites, - Sign of recovery ? But not on exotic species - Recent increase in anthropogenic pressure related: - less richness and abundance (([Newbold, Hudson, Hill, et al., 2015](https://www.nature.com/articles/nature14324))), more exotic species and turnover - Counter sign of recovery from past disturbance --- # Typology of biodiversity temporal trends Are the temporal trends of different biodiversity facets closely related or different ? --- # Typology of biodiversity temporal trends Five orthogonal biodiversity facets and six clusters of temporal change <img src="jasm2022_files/figure-html/unnamed-chunk-11-1.png" width="100%" /> --- # Spatial scale of change
--- # Take home message - Past and recent anthropogenic pressures interacts to drive biodiversity trends -- - Assessment of anthropogenic pressures partly resolves 10 years of debate: spatial vs temporal trends of biodiversity ([Dornelas, Gotelli, McGill, et al., 2014](https://science.sciencemag.org/content/344/6181/296); [Cardinale, Gonzalez, Allington, et al., 2018](https://linkinghub.elsevier.com/retrieve/pii/S000632071732089X); [Klink, Bowler, Gongalsky, et al., 2020](https://science.sciencemag.org/content/368/6489/417)) -- - Importance to assess multiple facets of biodiversity --- # Thanks <img src="/home/alain/Documents/thesis/talks/isu_biology_dept/collab_isu.png" width="100%" /> --- # Thanks We are indebt to all the researchers and agencies who monitored fish abundance through time and provided their data for this project. I am indebt to Lise Comte who performed the Herculean task to assemble and clean the database ([Comte, Carvajal-Quintero, Tedesco, et al., 2021](https://onlinelibrary.wiley.com/doi/abs/10.1111/geb.13210)). --- # Thanks Thank you for listening to me! --- # References